Video Studio has three tabs, and every tour you have ever made is in one of them.
Drafts holds tours you have started but not finished rendering. Open one to pick up where you left off.
Completed holds every finished tour. This is where you go to watch, download, or re-download something you made before. Nothing expires from here.
Favorites holds the tours you have starred, so the ones you send most often stay at the top.
A finished tour also appears in the property's own workspace and in your Media Library, so you can reach it from whichever direction you happen to be working.